Doctors recently reported the case of a 17-year-old boy with Alport syndrome who developed an even more rare disease — ANCA-associated vasculitis — and was successfully treated. This is the first-ever documented case of a patient with both diseases.
The case report, “ANCA vasculitis in a patient with Alport syndrome: a difficult diagnosis but a treatable disease!” appeared in the journal BMC Nephrology. Its authors emphasize the importance of considering a second condition when the primary known disease evolves in an atypical fashion.
Alport syndrome is rare genetic kidney disorder that causes glomerulonephritis (GN), or damage to tiny channels in the kidney where urine is filtered. Affecting one out of 50,000 newborns, it is characterized by hematuria and inconstant renal failure, hearing loss, lenticonus and retinal flecks.
ANCA (anti-neutrophil cytoplasmic autoantibody)-associated vasculitis is an even much less common in childhood, with an estimated annual incidence of less than one per 1,000,000 children. Unlike Alport, is not inherited. It is an autoimmune disease, caused by harmful autoantibodies and affecting many organs, such as the kidneys, leading to ANCA glomerulonephritis.
“The association of these two glomerular diseases has never been reported, to the best of our knowledge, and may be a coincidence,” the authors wrote, “although the low incidence of both diseases theoretically would argue against a coincidence.”
The patient was diagnosed at age 3 with X chromosome-linked Alport syndrome. At age 10, he began to show signs of deafness. At age 15, symptoms of kidney disease worsened.
Upon his admission to the hospital at age 17, he had symptoms of Alport syndrome as well as anemia, kidney failure and high levels of C-reactive protein — a naturally occurring protein that suggests persistent inflammation. These symptoms are not typical of Alport syndrome, which led researchers to suspect an additional disease. Further investigations uncovered ANCA-associated vasculitis. The patient was treated with steroids and anti-inflammatory drugs, which stabilized the vasculitis.
“Indeed, the initial diagnosis, although firmly established, did not account easily for many recent findings. We avoided thus the not-infrequent cognitive error in medical diagnosis, called premature closure,” authors said. “This case highlights the importance of being systematic in case of unusual evolution of a known glomerulopathy. A second type of acquired GN may be, very infrequently, present and should be diagnosed as early as possible, in order to start the appropriate drug regimen and alter the initially unfavorable course of the disease, as shown in our case.”